Adding Gear Oil to Differential Housing on My Dodge Ram?

On the outside of the differential housing on my Dodge Ram, there is a rubber boot with what looks like a plug in the middle. Is that in fact a plug, and does it have to be removed before adding the gear oil? If so, how do I remove it? Thanks!Adding Gear Oil to Differential Housing on My Dodge Ram?
Wipe off the area around it then pry it out with a flathead screwdriver and fill with gear lube until it runs out then replace plug.Adding Gear Oil to Differential Housing on My Dodge Ram?
yes that has to be removed before you can add to it,then all you do is fill it up to the point that it starts to come out,and that's it its full replace the plug and its done a very simple job to do,good luck on it.